Nagoya University, Panasonic Corporation and Japan Fine Ceramics Center have jointly succeeded in charging and discharging all-solid-state lithium-ion batteries and visualizing the distribution of lithium ions in the positive electrode material for the first time in the world.It is expected that next-generation batteries will be put into practical use.
All-solid-state lithium-ion batteries are next-generation batteries that can be expected to have high safety and high energy density.As one of the "innovative batteries" that can overcome the problems of conventional batteries using liquid electrolytes, research and development are being carried out all over the world for the purpose of mounting them in electric vehicles and hybrid vehicles.However, the all-solid-state lithium-ion battery has an extremely high transfer resistance of lithium ions at the electrode / solid electrolyte interface, which hinders practical use.
"Electron energy loss spectroscopy" can measure the energy lost when electrons pass through the inside of a sample and analyze the elements and electronic states in the material. "Advanced image analysis technology (multivariate analysis technology)" can clearly capture weak lithium signals on a nanometer scale.The research group will make full use of these new technologies possessed by the group to charge and discharge all-solid-state lithium-ion batteries in a scanning transmission electron microscope, and distribute lithium ions in the positive electrode material lithium cobalt oxide in the same region. And succeeded in quantitative visualization.
From this observation, it was found that lithium is unevenly distributed in the positive electrode, which also affects the movement of lithium ions during charging and discharging.It was also found that the concentration of lithium ions was low in the vicinity of the interface near the solid electrolyte, and a large amount of tricobalt tetroxide was mixed.
From this result, the cause of the high transfer resistance of lithium ions at the interface is clarified, and it is expected that great progress will be made toward the practical application of next-generation batteries.
